DEF Consumption

[Ekordas]

So my 2016 Duramax has roughly 1000 miles on it and the DEF level went from OK to 28%. Do they consume more when brand new, or did the dealer likely just not fill it?

[doverarjim]

Sounds like most of them, dealer did not fill it. I can get anywhere from 5500 miles to 8500 miles from a tank depending on how much and what I tow. It works out to about 1% of the fuel you burn. Enjoy the power!

[Colossus]

Correct. Fill it up with fresh stuff and you'll be good for 3000-5000 before needing to refill. I'm at about 4000 miles and have about 800 miles left according to my DIC.

[airman734]

My dealer told me they don't fill it up due to the fact that DEF is so sensitive about age. Once the truck is purchased they want you to get all the old stuff out of there and then put in fresh. My dealer filled it for free after I ran the old stuff mostly out.

[aeblank]

Sounds like a convenient excuse. Granted, there's some truth to it too. Most probably just buy their own and fill er up.

 

Sent from my XT1254 using Tapatalk

[20Denali22]

I have 2k on mine and haven't got a low level yet. I'm pretty sure my dealer filled mine up

[aminga]

It should be filled as part of the PDI. If they don't ask them to go back and fill it up.

[avalonandl]

A full DEF tank should last 4-5000 miles depending on city vs. highway.

 

I bet your dealer didn't fill it.

 

HINT: Fill the DEF tank SLOWLY= it likes to puke if you fill it too fast.

[20Denali22]

It should be filled as part of the PDI. If they don't ask them to go back and fill it up.

I had my first service and the dealer tech who filled my DEF tank left a series of scratches about 6 inches long on my quarter panel . Then it looked like he took a dry rag and wiped off his greasy hand prints on another section... I polished my black truck about 3 weeks ago to remove most of the swirls and there were NO scratches whatsoever so I'm a little upset..

[20Denali22]

My truck was down to 28% @ 5100 miles on the initial fill

[redwngr]

My dealer told me they don't fill it up due to the fact that DEF is so sensitive about age. Once the truck is purchased they want you to get all the old stuff out of there and then put in fresh. My dealer filled it for free after I ran the old stuff mostly out.

They got it half right. That's why they are not filled in Flint -- however the dealer is supposed to fill at PDI.

'DEF not filled' is one of the most common complaints on the dmax forums.

[redwngr]

So my 2016 Duramax has roughly 1000 miles on it and the DEF level went from OK to 28%. Do they consume more when brand new, or did the dealer likely just not fill it?

DEF is used in ratio to fuel burned. The correct ratio for the chemical process does not change.

 

FWIW, when computer calculates 30% or more it will read OK, less than that and it displays a % estimate.

[Black02Silverado]

Big difference on the trucks vs my Cruze diesel. My DEF lasted me 12k miles before I needed to add DEF.

 

Also, if there are any truck stops by you that have DEF at the pump, purchase it there. It is about the freshest stuff you can find and the least expensive. Here in eastern NC it is $2.70 a gallon. It is also easier to dispense and not make a mess. My tank is in my trunk and when I filled it up, it went smooth with no splashing.

 

DEF does have a shelf life. It degrades faster in hot temps.

 

Shelf life is on page 3 at the bottom.

[Cowpie]

I'll take that a step better. Stop in at any commercial truck dealership shop or commercial vehicle lube center if you have one near you and get DEF for a $1.80 a gallon at most. The Mack Dealership near me, and the commercial tire dealership I use, will fill any vehicle from their bulk DEF. Those guys go thru hundreds of gallons of DEF a week so the stuff is of good quality and fresh. They get it in 275 gallon totes and go thru several a week. They have better ways of padding their overhead costs instead of hitting the consumer at the pump like a truck stop outlet has to.

Edited November 24, 2016 by Cowpie

[EJCarter]

Mine was full when I took delivery of the truck. Dealer filled it for free at the first oil change (4000 miles) and the second (9000) miles. Prior to taking it in for both services, the def level always stated OK, so my consumption never dropped below the set point to trigger the % indicator.